Log Message:
p5-Type-Tiny-XS: update to 0.021.

0.021	2020-08-18

 [ Bug Fixes ]
 - Fix Enum test case for when Type::Parser is not available.

0.020	2020-08-17

 - Allow Enum[] to take a list of quoted strings rather than just
   barewords.
   Andrew Ruder++
   <https://github.com/tobyink/p5-type-tiny-xs/pull/12>

0.019	2020-08-05

 [ Packaging ]
 - Remove some cruft that was accidentally packaged.

0.018	2020-08-05

 [ Test Suite ]
 - Tests for InstanceOf

 [ Other ]
 - Slight speed boost for InstanceOf in cases where the object being tested
   overrides UNIVERSAL::isa.